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Active
faults
capable
of
generating
highly
damaging
earthquakes
may
not
cause
surface
rupture
(i.e.,
blind
faults)
or
cause
surface
ruptures
that
evade
detection
due
to
subsequent
burial
or
erosion
by
surface
processes.
Fault
populations
and
earthquake
frequency-­‐magnitude
distributions
adhere
to
power
laws,
implying
that
faults
too
small
to
cause
surface
rupture
but
large
enough
to
cause
localized
strong
ground
shaking
densely
populate
continental
crust.
The
rupture
of
blind,
previously
undetected
faults
beneath
Christchurch,
New
Zealand
in
a
suite
of
earthquakes
in
2010
and
2011,
including
the
fatal
22
February
2011
moment
magnitude
(Mw)
6.2
Christchurch
earthquake
and
other
large
aftershocks,
caused
a
variety
of
environmental
impacts,
including
major
rockfall,
severe
liquefaction,
and
differential
surface
uplift
and
subsidence.
All
of
these
effects
occurred
where
geologic
evidence
for
penultimate
effects
of
the
same
nature
existed.
To
what
extent
could
the
geologic
record
have
been
used
to
infer
the
presence
of
proximal,
blind
and
/
or
unidentified
faults
near
Christchurch?
In
this
instance,
we
argue
that
phenomena
induced
by
high
intensity
shaking,
such
as
rock
fragmentation
and
rockfall,
revealed
the
presence
of
proximal
active
faults
in
the
Christchurch
area
prior
to
the
recent
earthquake
sequence.
Development
of
robust
earthquake
shaking
proxy
datasets
should
become
a
higher
scientific
priority,
particularly
in
populated
regions.